Corn Disease: What Are Cutworms?

Young corn plants look sheared near to the soil? Could be the common corn disease known as cutworm damage. Find out more about this....

What is it?

Corn cutworms come in several species, the two most common of the species being the dingy cutworm or feltia ducens and the black cutworm or agrotis ipsilon. Just one cutworm can sever the stems of many young plants in the course of an evenings feeding, so as soon as cutworm damage is noted it must be treated to save your crop.

What does it look like?

Corn cutworms can be either black, brown or grey or a shade somehwere in this mix of dark colors. Typically corn cutworms grow to between 1.5 and 2 inches long and are often seen curled. The inside of their underbelly may appear lighter than their backs. Damage from corn cutworms results in young plants being chewed off at soil level at the stem. Often the damage will look as if someone took a pair of shears to the plants, cutting them close to the soil. Typically when cutworms are present they can be found at soil level and up to two inches deep in the soil. They will curl up even if they are only minimally disturbed.

How does it manifest?

Corn cutworms are the larvae of adult cutworms. Adult cutworms are dark moths that are nightflying and they typically have bands or stripes on the area of their forewings. Cutworms can breed several generations in a growing season as they lay eggs, pupate and emerge as mature adult moths. They can cause damage to plants as wither worms or moths, but moths chew the leaves, and do not cut or chew the stems at soil level.

What can you do about it?

Cutworm collars are effective in keeping worms off the plants. Collars can be made from stiff paper, tin cans, aluminum foil or even cardboard milk cartons. Be sure if you use collars that they are at least 2 inches high and are pressed firmly into the soil, preferably 2 inches deep. You can also control cutworm damage by applying insecticide containing ewither diazinon, chlorpyrifos or by using bait which contains carbaryl. Cutworms can be tenacious and difficult to control so applications of insecticide may have to be repeated regularly at one week intervals in order to control the cutworm population.